Three women who were born in the 1950s claim the raising of their pension age from 60 to 66 discriminates against them on the grounds of their age and sex, and that they were not properly informed of the changes in time to adjust.

Michael Mansfield QC, representing the claimants, told the High Court that the changes affected "a minimum of 3.8 million women", some of whom were given as little as 18 months' notice.

At a hearing in London on Friday, Mrs Justice Lang said the women's case was "arguable" and granted permission for their claim to proceed to a full hearing.

'Powerless'

The Government introduced changes to the state pension age, most recently in 2011, in an attempt to ensure "pension age equalisation", so that women's pension age matched that of men.

But Mr Mansfield said those women affected, who will have to wait up to six years longer for their pension, had been left in a "powerless" position, adding: "Suddenly they have to retrain, suddenly they have to find a new job."

He suggested the Government had "made it clear that the real object of this exercise has been cost-cutting and saving money", and that there was "no question of policy principle here".

Julian Milford, for the Department of Work and Pensions, said the changes were intended to bring about "the equalisation between genders of the age of entitlement for the state pension" and to "ensure as a matter of inter-generational fairness that working age taxpayers were not asked to shoulder an unreasonable funding burden".

He also conceded that it was intended to "help alleviate massive fiscal pressures following the financial crash of 2008", but added: "This is not simply a question of cost."

After the hearing, Yvette Greenway from the Back to 60 campaign said: "This is such an important step and this has made such a difference to so many '50s women.

"Today, hearing this result, it is what they have prayed for, what they have worked towards for a long time.